Grating



May 13, 1958 G. T. BEEBE 2,834,267

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1 Claim. (Cl. 94-30) This invention relates to improvements in grating structures.

The invention is concerned particularly with the type of grating which comprises slotted main longitudinal bars and transverse lacing bars interlocked therewith'. Such gratings are shown, for example, in Greulich Patents No. 2,089,891, dated August l0, 1937, No. 2,275,104, dated March 3, 1942, and No. 2,275,105, dated March 3, 1942, or Lienhard Patent No. 2,128,753, dated August 30, 1938. The procedure in assembling such gratings is to space the main longitudinal bars the proper distance apart with their slots aligned, orient the lacing bars with their longer cross-sectional dimensions horizontal and insert them through the slots, and then turn the lacing bars 90 on their longitudinal axes to a position where these longer dimensions are upright. Thereafter tertiary longitudinal bars can be added intermediate the main bars, and the various bars are welded at all their intersections to form a rigid structure. These gratings sometimes include additional elements, such as bottom bars or concrete retaining pans, not involved in the present invention.

Until the welds are applied, the lacing bars t rather loosely in the slots of the main longitudinal bars. I have observed that such looseness leads to disadvantages. After the lacing bars are turned upright, they can tip back, and it is possible to weld them on a bias, which prevents solid `seating of the tertiary bars thereon. The heat of welding the lacing bars to the main longitudinal bars sometimes produces undesirable camber in the latter. After such gratings are installed in bridges or roadways, breakage of one weld often is followed by progressive breakage of all the welds along a particular lacing bar, whereupon this ybar tips over and rattles until rewelded.

An object of the present invention is to provide an improved grating yof the foregoing type wherein the lacing bars are positively interlocked with the main longitudinal bars, thus eliminating welds and overcoming the foregoing disadvantages.

A more specific object is to provide an improved grating of the foregoing type which includes wedge bars iuserted in the slots of the main longitudinal bars underneath the lacing bars for positively holding these bars in tight interlocking relation.

In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawings, in which:

Figure 1 is a perspective view of a grating constructed in accordance with my invention;

Figure 2 is a vertical section showing one of the slots in a main longitudinal bar with a wedge bar and a lacing bar inserted in their initial positions;

Figure 3 is a view similar to Figure 2, but showing the lacing bar turned upright;

Figure 4 is another view similar to Figure 2, but showing both the wedge bar and the lacing bar in their nal positions;

Figure 5 is a section on line V-V of Figure 3; and

A2,834,267 'Patented May 13, 12958 -Figure 6 is a section on line VI--VI of Figure 4.

Figure 1 -shows a grating which comprises a plurality of spaced parallel main longitudinal bars 10, a plurality of spaced parallel lacing bars 12, tertiary longitudinal bars 13 intermediate the main bars, and bottom bars 14. The main longitudinal bars 10 have a modied I-beam cross section and they contain slots 15 of inverted =L shape. The lacing bars are of rectangular cross section and the upper edge of each contains a rst series of notches 16, which receive the portions of the main" longitudinal bars immediately above the slots 15, and a second series of notches 17 which receive the tertiary bars 13. The bottoni `bars 14 are of circular cross section and pass through the main longitudinal bars 10 at locations spaced below the lacing bars 12. p

In accordance with my invention, each row of slots 15 contains a wedge bar 18 beneath the lacing bar 12 therein. The wedge bars are of rectangular cross section, and the bottom edge of each contains a series of notches 19 spaced the same distance apart as the spacing between the main bars 10. The rearward portion of each notch has a wedge surface 20.

When my improved grating is assembled, the main longitudinal bars 10 are positioned as usual and the bottom bars 14 installed. Next the wedge bars 18 are inserted through the vertical legs `of the slots 15 to a position where their notches 19 register with said slots. The lacing bars 12 are oriented with their longer cross sectional dimensions horizontal and are inserted through the horizontal legs of the slots 15 to a position where their notches 16 register with said slots (Figure 2). These bars then are rotated as usual on their longitudinal axes into the vertical legs of the slots and they assume an upright position (Figures 3 and 5). The wedge bars 18 are driven ahead and their wedge surfaces 20 ride up the lower edges of the slots until the body of each wedge bar -behind its notches 19 is positioned within the vertical legs of the slots 15 (Figures 4 and 6).

Before the wedge bars 18 are driven to their final positions, their notches 19 allow a substantial clearance in the vertical legs of the slots 15 over the vertical dimensions of the portions of the lacing bars 12 received therein, as shown in Figures 3 and 5. Referring to the aforementioned Greulich patents, it is seen that the vertical legs of the corresponding slots and the portions of the lacing bars received therein are of practically equal heights. This additional clearance enables me to shape the slots 15 to cooperate with the Wedge bars 18 for positively interlocking the lacing bars 12 with the main longitudinal bars 10. For this purpose the slot edges have upper and lower shoulders 21 and 22 at the intersections between their horizontal and vertical legs. The upper edge of each horizontal leg has a recess 23 which enables the lacing bars to be turned into upright position. After the wedge bars 18 are driven to their final positions, the lacing bars 12 are situated behind the shoulders 21 and 22, and the combined height of the wedge bars and lacing bars furnishes a snug t against the top and bottom edges of the vertical legs of the slots 15, as shown in Figures 4 and 6.

After the lacing bars V12 and wedge bars 18 are assembled with the main longitudinal bars 10, the tertiary longitudinal bars 13 are inserted in the notches 17. The intersections between the bars 12 and 13 and those between the bars 10 -and 14 are `welded in the usual way, as indicated at 24 and 25, respectively. The positive interlock between the bars 10, 12 and 18 eliminates any need for welding their intersections, and yet assures that the lacing bars 12 remain upright at all times. The only additional welds needed are tack welds 26 between the bars 12 and 18 adjacent their ends. Thus my grating materially reduces the number of welds required over the 3 gratings shown in the aforementioned patents. In practice my grating requires only about eight welds per square foot of grating surface while the others require about 26.

While I have shown and described only a single embodiment of the invention, it isV apparent that modications may arise. Therefore, I do not wish to be'limited to the disclosure set forth but only by the scope of the appended claim.

I claim:

A grating comprising a plurality of spaced .parallel mainlongitudinal bars having aligned slots, a plurality ot' transverse lacing bars extending through said slots and having notches in their upper edges receiving the upper portions of the said main bars, and a plurality of wedge bars corresponding with said lacing bars and extending through said slots underneath the respective lacing bars, each of said slots having an enlarged horizontal portion and upper and lower vertical leg portions merging into said horizontal portion and forming upper and lower shoulders, each of said Wedge bars having a plurality of spaced notches in its bottom edge adapted to register with the respective main bars, the rearward portions of said last named notches being inclined to form wedge surfaces, said lacing bars being insertable in the horizontal portions of said slots and rotatable through the enlargements into the vertical leg portions when the notches in said wedge bars are in registry with said main bars, said wedge bars locking said lacing bars behind said upper and lower shoulders when moved in the direction of their length so that their notches are out of registry with said main bars.

References Cited in the le of this patent UNITED STATES PATENTS 2,084,118 Zabriskie June 15, 1.937 2,275,104 Gremien Mar. 3, 1942 FOREIGN PATENTS 321,-706 Great Britain Nov. 1s, 1929 

